APPENDIX E
Noise and Vibration Technical Report
Prepared for:
City of Riverside, Community and Economic
Development Department
3900 Main Street, #5
Riverside, CA 92522
Prepared by:
Impact Sciences, Inc.
811 W. 7th Street, Suite 200
Los Angeles, CA 90017
Contact: Brett Pomeroy, Associate Principal
Mikasa Luxury Villas
Residential Development Project
Noise and Vibration
Technical Report
July 2025
Impact Sciences, Inc. i Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025
TABLE OF CONTENTS
Section Page
1.0 Introduction .................................................................................................................................................. 1
1.1 Project Location .............................................................................................................................. 1
1.2 Project Description ......................................................................................................................... 1
2.0 Environmental Setting ................................................................................................................................. 5
2.1 Fundamentals of Noise & Vibration ............................................................................................ 5
2.2 Noise Sensitive Receptors ........................................................................................................... 10
2.3 Existing Conditions ...................................................................................................................... 11
3.0 Regulatory Framework .............................................................................................................................. 14
3.1 State Regulations .......................................................................................................................... 14
3.2 Local Plans and Policies .............................................................................................................. 15
4.0 Noise Analysis ............................................................................................................................................ 21
4.1 Thresholds of Significance .......................................................................................................... 22
4.2 Methodology ................................................................................................................................. 22
4.3 Impact Analysis ............................................................................................................................ 23
5.0 References .................................................................................................................................................... 27 Appendix
A – Noise and Vibration Technical Data
LIST OF FIGURES
Figure Page
1 Aerial Photo of the Project Site ................................................................................................................... 3 2 Project Site Plan ............................................................................................................................................ 4 3 Noise Monitoring & Sensitive Receptor Location Map ..........................................................................13
LIST OF TABLES
Table Page
1 Project Features ............................................................................................................................................. 2 2 A-Weighted Decibel Scale ........................................................................................................................... 6 3 Building Noise Reduction Factors.............................................................................................................. 7 4 Existing Noise Levels in the Vicinity of the Project Site ........................................................................ 11 5 Construction Vibration Damage Criteria ................................................................................................ 15 6 Guideline Vibration Damage Potential Threshold Criteria .................................................................. 16 7 Noise / Land Use Compatibility Matrix .................................................................................................. 18 8 Exterior Noise Standards ........................................................................................................................... 20 9 Estimated Exterior Construction Noise at Sensitive Receptors ........................................................... 24 10 Vibration Levels at Off-Site Structures from Project Construction ..................................................... 27 Impact Sciences, Inc. 1 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report - July 2025
1.0 INTRODUCTION
The purpose of this report is to evaluate the potential for noise and groundborne vibration impacts associated with the proposed project located at 4618 Jones Avenue, 4705 Hedrick Avenue, and 4663 Hedrick Avenue (Project) within the City of Riverside (City) in Riverside County (County). This report includes an evaluation of potential impacts associated with substantial temporary and permanent increases in ambient noise levels in the vicinity of the Project Site; exposure of people in the vicinity of the Project Site to excessive noise or groundborne vibration levels; and whether exposure is in excess of standards established in the City’s General Plan or Noise Ordinance. This report has been prepared by Impact Sciences, in support of the environmental documentation being prepared pursuant to the California Environmental Quality Act (CEQA).
1.1 PROJECT LOCATION
The applicant proposes to consolidate three parcels and develop 117 multifamily units (“Project”). The Project would be located at 4618 Jones Avenue, 4705 Hedrick Avenue, and 4663 Hedrick Avenue (APN# 143-040-010, 143- 040-011, and 143- 040-012; “Project Sit e”) in the City of Riverside. The Project Site is approximately 4.54 acres and is in the western portion of the City. The Project Site is located east of Hedrick Avenue, west of Jones Avenue, north of Hole Avenue, and south of Wells Avenue ( see Figure 1, A eria l
Ph
otograph of the Project Site).
1.2 PROJECT DESCRIPTION
The Project Site currently is predominantly undeveloped but contains three single- family residences, two mobile homes, and four storage sheds. The Project Site is surrounded by two -story multifamily residences located south of the Project Site and one-story single-family residences to the west, north, and east. Parcels 143-040-010 and 143 -040-011 have a land use designation of Medium D ensity Residential (MDR) and are zoned for Single-Family Residential (R -1-7000). Parcel 143-040-012 has a land use designation of Hig h D
ensity Residential (HDR) and is zoned for Multiple-Family Residential (R -3-1500). The Project is proposing to amend the current general plan designation for parcels 143 -040-010 and 143 -040-011 from MDR to HDR; the Project is also proposing to rezone these parcels from R-1-7000 to R-3-1500. See Figure 1, Aerial Photograph of the Project Site.
Proposed Project
The Project includes the demolition of all existing structures on site: 4618 Jones Avenue, 4663 Hedrick Avenue, and 4705 Hedrick Avenue. According to documentation from the County Assessor, the square
1.0 Introduction
Impact Sciences, Inc. 2 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025 f
ootage of the existing buildings are: 1,462 square feet, 2,157 square feet, and 668 square feet, respectively (a total of 4,287 square feet of buildings to be demolished). The Project includes the construction of approximately 193,421 square feet of new development. In addition, the Project would include approximately 80,803 square feet of open space (common, private, and public). The Project would include 15 multifamily buildings, containing 117 dwelling units, a community hall, gym, pool, spa, and tot lot/play area. The dwelling units would range from studios to two bedrooms. See Figure 2, Project Site Plan and Table 1, Project Features.
Table 1
Project Features
Project Features Type Stories Maximum
Height
Number
of Units
Building
Area Square
Footage (sq.
ft.)
Building A 1 2 25’ 4” 3 4,415
Building B 1R 2 25’ 4” 3 4,415
Building C 1 2 25’ 4” 3 4,415
Building D 1R 2 25’ 4” 3 4,415
Building E 2 2 25’ 4” 3 4,415
Building F 2 2 25’ 4” 3 4,415
Building G 2 2 25’ 4” 3 4,415
Building H 3 2 25’ 4” 6 8,492
Building I 4 2 25’ 4” 7 9,851
Building J 5 3 41’ 8” 14 24,310
Building K 6 3 41’ 8” 14 23,517
Building L 6R 3 41’ 8” 14 23,517
Building M 5R 3 41’ 8” 14 24,310
Building N 5R 3 41’ 8” 14 24,310
Building O 7 2 25’ 4” 10 17,149
Building P (Manager Units and Leasing Office) 8 2 25’ 4” 3 3,664 Building Q (Community Hall and Gym) 9 2 25’ 4” - 3,396
Total 117 units 193,421 sq. ft.
Source: G&G Engineering, Inc., Sheet C-1.1, September 15, 2021.
Hedrick
Ave
Hedrick
Ave
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Jones
Ave
Jeri Dr
Jones
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Cook Ave
Vista Grande
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0 250125
US Feet
City of Riverside, Maxar, Esri Community Maps Contributors, City of Riverside, County of Riverside, County of San Bernardino, California State Parks, © OpenStreetMap, Microsoft, Esri, HERE, Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA, USGS, Bureau of Land Management, EPA, NPS, US Census Bureau, USDA Project Site
Aerial Photograph of the Project Site
FIGURE 1
1558.001•08/2023
SOURCE: Esri, 2023
Project Site Plan
FIGURE 2
1558.001•11/2025
SOURCE: G&G Engineering, 2025
Impact Sciences, Inc. 5 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report - July 2025
2.0 ENVIRONMENTAL SETTING
2.1 FUNDAMENTALS OF NOISE & VIBRATION
Noise
Noise is usually defined as unwanted sound that is an undesirable byproduct of society’s normal day- to- day activities. Sound becomes unwanted when it interferes with normal activities, when it causes actual physical harm, and/or when it has adverse effects on health. Noise is measured on a logarithmic scale of sound pressure level known as a decibel (dB). The human ear does not respond uniformly to sounds at all frequencies. For example, the human ear is less sensitive to low and high frequencies than mediu m frequencies, which more closely correspond with human speech. In response to the sensitivity of the human ear to different frequencies, the A -weighted noise level (or scale), which corresponds better with people’s subjective judgment of sound levels, has been developed. This A-weighted sound level, referenced in units of dB(A), is measured on a logarithmic scale such that a doubling of sound energy results in a 3 dB(A) increase in noise level. Typically, changes in a community noise level of less than 3 dB(A) are not noticed by the human ear
.1 Changes from 3 to 5 dB(A) may be noticed by some individuals who are sensitive to changes in noise. A greater than 5 dB(A) increase is readily noticeable, while the human ear perceives a 10 dB(A) increase in sound level to be a doubling of sound.
On the A-weighted scale, the range of human hearing extends from approximately 3 to 140 dB(A). Table 2, A-Weighted Decibel Scale, provides examples of A-weighted noise levels from common sources. Noise sources occur in two forms: (1) point sources, such as stationary equipment or individual motor vehicles; and (2) line sources, such as a roadway with a large number of point sources (motor vehicles). Sound generated by a point source typically diminishes (attenuates) at a rate of 6 dB(A) for each doubling of distance from the source to the receptor at acoustically “hard” sites and 7.5 dB(A) at acoustically “soft” sites.2 For example, if a noise source produces a noise level of 89 dB(A) at a reference distance of 50 feet, the noise level would be 83 dB(A) at a distance of 100 feet from the noise source, 77 dB(A) at a distance of 200 feet, and so on. Noise generated by a mobile source will decrease by approximately 3 dB(A) over hard surfaces and 4.5 dB(A) over soft surfaces for each doubling of distance.
1 California Department of Transportation (Caltrans), Technical Noise Supplement to the Traffic Noise Analysis Protocol, 2013. Available online at: https://dot.ca.gov/-/media/dot-media/programs/environmental- analysis/documents/env/tens-sep2013-a11y.pdf, accessed August 1, 2023. 2 Federal Highway Administration, Highway Noise Fundamentals, (1980) 97. Examples of “hard” or reflective sites include asphalt, concrete, and hard and sparsely vegetated soils. Examples of acoustically “soft” or absorptive sites include soft, sand, plowed farmland, grass, crops, heavy ground cover, etc.
2.0 Environmental Setting
Impact Sciences, Inc. 6 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025 Table 2
A-Weighted Decibel Scale
Typical A-Weighted Sound Levels Sound Level (dB(A), Leq) Threshold of Pain 140
Jet Takeoff at 100 Meters 125
Jackhammer at 15 Meters 95
Heavy Diesel Truck at 15 Meters 85
Conversation at 1 Meter 60
Soft Whisper at 2 Meters 35
Source: United States Occupational Safety & Health Administration, Noise and Hearing Conservation Technical Manual, 1999.
Sound levels also can be attenuated by man-made or natural barriers (e.g., sound walls, berms, and ridges), as well as elevational differences. Noise is most audible when traveling by direct line -of-sight, an interrupted visual path between the noise source and noise receptor. Barriers, such as walls or buildings that break the line -of-sight between the source and the receiver, can greatly reduce noise levels from the source since sound can only reach the receiver by diffraction. However, if a barrier is no t high or long enough to break the line-of-sight from the source to the receiver, its effectiveness is greatly reduced.
Solid walls and berms may reduce noise levels by 5 to 10 dB(A) depending on their height and distance relative to the noise source and the noise receptor.
3 Sound levels may also be attenuated 3 dB(A) by a first row of houses and 1.5 dB(A) for each additional row of houses.4 The minimum noise attenuation provided by typical structures in California is provided in Table 3, Building Noise Reduction Factors. 3 Federal Highway Administration, Highway Noise Mitigation, (1980) 18. 4 California Department of Transportation (Caltrans), Technical Noise Supplement to the Traffic Noise Analysis Protocol, 2013. Available at: https://dot.ca.gov/-/media/dot-media/programs/environmental- analysis/documents/env/tens-sep2013-a11y.pdf
2.0 Environmental Setting
Impact Sciences, Inc. 7 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025
Table 3
Building Noise Reduction Factors
Building Type Window Condition
Noise Reduction Due to
Exterior of the Structure
(dB(A))
All Open 10
Light Frame
Ordinary Sash (closed) 20
Storm Windows 25
Masonry
Single Glazed 25
Double Glazed 35
Source: Federal Highway Administration, Highway Traffic Noise: Analysis and Abatement Guidance. December 2011.
Sound Rating Scales
Various rating scales approximate the human subjective assessment to the “loudness” or “noisiness” of a sound. Noise metrics have been developed to account for additional parameters, such as duration and cumulative effect of multiple events. Noise metrics are categorized as single event metrics and cumulative metrics, as summarized below.
In order to simplify the measurement and computation of sound loudness levels, frequency weighted networks have obtained wide acceptance. The A -weighted scale, discussed above, has become the most prominent of these scales and is widely used in community noise analysis. Its advantages are that it has shown good correlation with community response and is easily measured. The metrics used in this analysis are all based upon the dB(A) scale.
Equivalent Noise Level
Equivalent Noise Level (Leq) is the sound level corresponding to a steady- state A-weighted sound level containing the same total energy as several single event noise exposure level events during a given sample period. Leq is the “acoustic energy” average noise level during the period of the sample. It is based on the observation that the potential for noise annoyance is dependent on the total acoustical energy content of the noise. The equivalent noise level is expressed in units of dB(A). Leq can be measured for any period, but is typically measured for 15 minutes, 1 hour, or 24 hours. Leq for a 1-hour period is used by the Federal Highway Administration (FHWA) for assessing highway noise impacts. Leq for 1 hour is referred to as the Hourly Noise Level (HNL) in the California Airport Noise Regulations and is used to develop Community
2.0 Environmental Setting
Impact Sciences, Inc. 8 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025 Noise Equivalent Level values for aircraft operations. Construction noise levels and ambient noise measurements in this section use the Leq scale.
Community Noise Equivalent Level
Community Noise Equivalent Level (CNEL) is a 24-hour, time-weighted energy average noise level based on the A-weighted decibel. It is a measure of the overall noise experienced during an entire day. The term “time-weighted” refers to the penalties attached to noise events occurring during certain sensitive periods.
In the CNEL scale, 5 decibels (dB) are added to measured noise levels occurring between the hours of 7 P.M. and 10 P.M. For measured noise levels occurring between the hours of 10 P.M. and 7 A.M., 10 dB are added.
These decibel adjustments are an attempt to account for the higher sensitivity to noise in the evening and nighttime hours and the expected lower ambient noise levels during these periods. Existing and projected future traffic noise levels in this section use the CNEL scale.
Day-Night Average Noise Level
The day-night average sound level (Ldn) is another average noise level over a 24-hour period. Noise levels occurring between the hours of 10 P.M. and 7 A.M. are increased by 10 dB . This noise is weighted to take into account the decrease in community background noise of 10 dB(A) during this period. Noise levels measured using the Ldn scale are typically similar to CNEL measurements.
Adverse Effects of Noise Exposure
Noise is known to have several adverse effects on humans, which has led to laws and standards being set to protect public health and safety, and to ensure compatibility between land uses and activities. Adverse effects of noise on people include hearing loss, communication interference, sleep interference, physiological responses, and annoyance. Each of these potential noise impacts on people is briefly discussed in the following narrative.
Hearing Loss
Hearing loss is generally not a community noise concern, even near a major airport or a major freeway. The potential for noise-induced hearing loss is more commonly associated with occupational noise exposures in heavy industry, very noisy work environment s with long -term exposure, or certain very loud recreational activities (e.g., target shooting and motorcycle or car racing). The Occupational Safety and Health Administration (OSHA) identifies a noise exposure limit of 90 dB(A) for 8 hours per day to prot ect from hearing loss (higher limits are allowed for shorter duration exposures). Noise levels in neighborhoods, even in very noisy neighborhoods, are not sufficiently loud enough to cause hearing loss.
2.0 Environmental Setting
Impact Sciences, Inc. 9 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025 Communication Interference
Communication interference is one of the primary concerns in environmental noise. Communication interference includes speech disturbance and intrusion with activities such as watching television. Noise can also interfere with communications such as within school classrooms. Normal conversational speech is in the range of 60 to 65 dB(A) and any noise in this range or louder may interfere with speech.
Sleep Interference
Noise can make it difficult to fall asleep, create momentary disturbances of natural sleep patterns by causing shifts from deep to lighter stages, and cause awakening. Noise may even cause awakening that a person may or may not be able to recall.
Physiological Responses
Physiological responses are those measurable effects of noise on people that are realized as changes in pulse rate, blood pressure, and other physical changes. Studies to determine whether exposure to high noise levels can adversely affect human health hav e concluded that, while a relationship between noise and health effects seems plausible, there is no empirical evidence of the relationship.
Annoyance
Annoyance is an individual characteristic and can vary widely from person to person. Noise that one person considers tolerable can be unbearable to another of equal hearing capability. The level of annoyance depends both on the characteristics of the noise (including loudness, frequency, time, and duration), and how much activity interference (such as speech interference and sleep interference) results from the noise.
However, the level of annoyance is also a function of the attitude of the receiver. Attitu des may also be affected by the relationship between the person affected and the source of noise, and whether attempts have been made to abate the noise.
Vibration
Vibration consists of waves transmitted through solid material. Groundborne vibration propagates from a source through the ground to adjacent buildings by surface waves. Vibration may comprise a single pulse, a series of pulses, or a continuous oscillatory motion. The frequency of a vibrating object describes how rapidly it is oscillating and is measured in hertz (Hz). Most environmental vibrations consist of a composite, or “spectrum” of many frequencies, and are generally classified as broadband or random vibrations. The normal frequency range of most groundborne vibration that can be felt generally starts from a low frequency of less than one Hz to a high of about 200 Hz. Vibration is often measured in terms of the peak
2.0 Environmental Setting
Impact Sciences, Inc. 10 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025 particle velocity (PPV) in inches per second (in/sec) when considering impacts on buildings or other structures, as PPV represents the maximum instantaneous peak of vibration that can stress buildings.
Because it is a representation of acute vibration, PPV is often used to measure the temporary impacts of short-term construction activities that could instantaneously damage -built structures. Vibration is often also measured by the root mean squared (RMS) because it best correlates with human perception and response. Specifically, RMS represents “smoothed” vibration levels over an extended period of time and is often used to gauge the long -term chronic impact of a Project ’s operation on the adjacent environment.
RMS amplitude is the average of a signal’s squared amplitude. It is most commonly measured in decibel notation (VdB).
Vibration energy attenuates as it travels through the ground, causing the vibration amplitude to decrease with distance away from the source. High frequency vibrations reduce much more rapidly than low frequencies, so that in the far-field from a source, the low frequencies tend to dominate. Soil properties also affect the propagation of vibration. When groundborne vibration interacts with a building, there is usually a ground-to-foundation coupling loss (i.e., the foundation of the structure does not move in sync with the ground vibration), but the vibration can also be amplified by the structural resonances of the walls and floors. Vibration in buildings is typically perceived as rattling of windows or items on shelves, or the motion of building surfaces. At high levels, vibration can result in damage to structures.
Manmade groundborne vibration is generally limited to areas within a few hundred feet of certain types of construction activities, especially pile driving. Road vehicles rarely create enough groundborne vibration to be perceptible to humans unless the road surface is poorly maintained and there are potholes or bumps.
If traffic induces perceptible vibration in buildings, such as window rattling or shaking of small loose items (typically caused by heavy trucks in passing), then it is most likely an effect of low-frequency airborne noise or ground characteristics. Human annoyance by vibration is related to the number and duration of events.
The more events or the greater the duration, the more annoying it will be to humans.
2.2 NOISE SENSITIVE RECEPTORS
Noise-sensitive land uses are generally considered to include those uses where noise exposure could result in health-related risks to individuals, as well as places where quiet is an essential element of their intended purpose. Residential dwellings are of primary concern because of the potential for increased and prolonged exposure of individuals to both interior and exterior noise levels. Additional land uses such as parks, historic sites, cemeteries, and recreation areas are considered sensitive to increases in exterior noise levels.
Schools, churches, hotels, libraries, and other places where low interior noise levels are essential are also considered noise-sensitive land uses. The closest noise -sensitive receptors to the Project Site include the adjacent residences to the north and south of the Project Site as well as the residences to the west on Hedrick
2.0 Environmental Setting
Impact Sciences, Inc. 11 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025 Avenue (40 feet) and to the east on Jones Avenue (54 feet). See Figure 3, Noise Monitoring and Sensitive Receptor Location Map.
2.3 EXISTING CONDITIONS
Measured Ambient Noise Levels
To establish baseline noise conditions, existing noise levels were monitored at three locations in the vicinity of the Project Site. The locations of where the noise measurements were taken are depicted in Figure 3, Noise Monitoring and Sensitive Receptor Location Map . The noise survey was conducted in July 2023 using the Larson Davis SoundTrack LxT (Type 1) sound level meter, which conforms to industry standards set forth in ANSI S1.4 -1983 (R2006) – Specification for Sound Level Meters/Type 1. This instrum ent was calibrated and operated according to the manufacturer’s written specifications. At the measurement sites, the microphone was placed at a height of approximately five feet above grade. The results of the measurements are summarized in Table 4, Existing Noise Levels in the Vicinity of the Project Site . As shown in Table 4, the daytime ambient noise levels ranged from 60.3 dB(A) Leq to 64.8 dB(A) Leq in the vicinity of the Project Site.
Table 4
Existing Noise Levels in the Vicinity of the Project Site
Noise Monitoring Locations Primary Noise Sources Noise Levels [dB(A)] Leq Lmin Lmax
1. Adjacent residences to the north Vehicle Traffic, Neighborhood Activity 61.6 55.1 79.3
2. Residences to the east on Jones Avenue Vehicle Traffic, Neighborhood Activity 60.3 56.1 77.7
3. Residences to the west on Hedrick Avenue Vehicle Traffic, Neighborhood Activity 64.8 53.1 80.3
Source: Impact Sciences, Inc., July 2023. See Appendix A, Noise and Vibration Technical Data.
Hedrick
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1 1
2 3
4 0 250125
US Feet
City of Riverside, Maxar, Esri Community Maps Contributors, City of Riverside, County of Riverside, County of San Bernardino, California State Parks, © OpenStreetMap, Microsoft, Esri, HERE, Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA, USGS, Bureau of Land Management, EPA, NPS, US Census Bureau, USDA Project Site
Noise Monitoring Loca�ons
Sensi�ve Receptors
#
#
Noise Monitoring and Sensitive Receptor Locations Map
FIGURE 3
1558.001•08/2023
SOURCE: Esri, 2023
2.0 Environmental Setting
Impact Sciences, Inc. 13 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025 Existing Groundborne Vibration Levels
The main sources of groundborne vibration near the Project Site are heavy -duty vehicular travel (e.g., delivery trucks and transit buses) on local roadways. Trucks and buses typically generate groundborne vibration velocity levels of around 63 VdB at 50 feet, and these levels could reach 72 VdB where trucks and buses pass over bumps in the road.5 In terms of PPV levels, a heavy-duty vehicle traveling at a distance of 50 feet can result in a vibration level of approximately 0.001 inch per second.
5 Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual, 2018. Available at:
https://www.transit.dot.gov/sites/fta.dot.gov/files/docs/research-innovation/118131/transit-noise-and-vibration- impact-assessment-manual-fta-report-no-0123_0.pdf, accessed August 1, 2023.
Impact Sciences, Inc. 14 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report - July 2025
3.0 REGULATORY FRAMEWORK
3.1 FEDERAL REGULATIONS
Occupational Health and Safety Act of 1970
Under the Occupational Safety and Health Act of 1970 (29 U.S.C. §1919 et seq.), the Occupational Safety and Health Administration (OSHA) has adopted regulations designed to protect workers against the effects of occupational noise exposure. These regulations list permissible noise level exposure as a function of the amount of time during which the worker is exposed. The regulations further specify a hearing conservation program that involves monitoring noise to which workers are exposed, ensuring that worke rs are made aware of overexposure to noise, and periodically testing the workers’ hearing to detect any degradation. 6 Noise Control Act of 1972
Under the authority of the Noise Control Act of 1972, the United States Environmental Protection Agency (U.S. EPA) established noise emission criteria and testing methods published in Parts 201 through 205 of Title 40 of the Code of Federal Regulations (CFR) that apply to some transportation equipment (e.g., interstate rail carriers, medium trucks, and heavy trucks) and construction equipment. In 1974, U.S. EPA issued guidance levels for the protection of public health and welfare in residential areas of an outdoor Ldn of 55 dB(A) and an indoor L dn of 45 dB(A). These guidance levels are not standards or regulations and were developed without consideration of technical or economic feasibility. There are no federal noise standards that directly regulate environmental noise related to the construction or operation of the Project.
Moreover, the federal noise standards are not reflective of urban environments that range by land use, density, proximity to commercial or industrial centers, etc. As such, for purposes of determining acceptable sound levels to determine and evaluate intrusive noise sources and increases, this document utilizes the City of Riverside Noise Regulations, discussed below.
Federal Transit Administration Vibration Standards
There are no federal vibration standards or regulations adopted by any agency that are applicable to evaluating vibration impacts from activities associated with the Project. However, the Federal Transit Administration (FTA) has adopted vibration criteria for use in evaluating vibration impacts from construction activities. The vibration damage criteria adopted by the FTA are shown in Table 5, Construction Vibration Damage Criteria.
6 United States Department of Labor, Occupational Safety and Health Act of 1970. Available online at:
https://www.osha.gov/laws-regs/oshact/completeoshact, accessed August, 2023.
3.0 Regulatory Framework
Impact Sciences, Inc. 15 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025
Table 5
Construction Vibration Damage Criteria
Building Category PPV (in/sec)
I. Reinforced-concrete, steel, or timber (no plaster) 0.5 II. Engineered concrete and masonry (no plaster) 0.3
III. Non-engineered timber and masonry buildings 0.2
IV. Buildings extremely susceptible to vibration damage 0.12
Source: FTA, Transit Noise and Vibration Impact Assessment Manual, 2018.
3.2 STATE REGULATIONS
Office of Planning and Research Guidelines for Noise Compatible Land Use The State of California has not adopted statewide standards for environmental noise, but the Governor’s Office of Planning and Research (OPR) has established guidelines for evaluating the compatibility of various land uses as a function of community noise exposure. The City has developed its own compatibility guidelines in the Noise Element of the General Plan based in part on OPR Guidelines, see Table 7 and Table 8, later in this report. California Government Code Section 65302 requires each county and cit y in the State to prepare and adopt a comprehensive long-range general plan for its physical development, with Section 65302(f) requiring a noise element to be included in the general plan. The noise element must: (1) identify and appraise noise problems in the community; (2) recognize Office of Noise Control guidelines; and (3) analyze and quantify current and projected noise levels.
Caltrans Vibration / Groundborne Noise Standards
The State of California has not adopted Statewide standards or regulations for evaluating vibration or groundborne noise impacts from land use development projects. Although the State has not adopted any vibration standard, Caltrans recommends the following vibration thresholds that are more practical than those provided by the FTA.
7 The state noise and vibration guidelines are to be used as guidance with respect to planning for noise, not standards and/or regulations to which the City of Riverside must adhere.
7 Caltrans, Transportation and Construction Vibration Guidance Manual, 2020.
3.0 Regulatory Framework
Impact Sciences, Inc. 16 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025
Table 6
Guideline Vibration Damage Potential Threshold Criteria
Structure and Condition
Maximum PPV (inch/sec)
Transient Sources1 Continuous/Frequent
Intermittent Sources2
Extremely fragile historic buildings, ruins, ancient monuments 0.12 0.08 Fragile buildings 0.20 0.10
Historic and some old buildings 0.50 0.25
Older residential structures 0.50 0.30
New residential structures 1.00 0.50
Modern industrial/commercial buildings 2.00 0.50
Source: Table 19, Transportation and Construction Vibration Guidance Manual (Caltrans 2020). 1 Transient sources create a single, isolated vibration event, such as blasting or drop balls. 2 Continuous/frequent intermittent sources include impact pile drivers, pogo -stick compactors, crack -and-seat equipment, vibratory pile drivers, and vibratory compaction equipment.
Title 24, California Code of Regulations
The California Noise Insulation Standards of 1988 (California Code of Regulations Title 24, Section 3501 et seq.) require that interior noise levels from the exterior sources not exceed 45 dB(A) Ldn/community noise equivalent level (CNEL) 8 in any habitable room of a multi -residential use facility (e.g., hotels, motels, dormitories, long-term care facilities, and apartment houses and other dwellings, except detached single- family dwellings) with doors and windows closed. Where exterior noise levels exceed 60 dB(A) CNEL/Ldn, an acoustical analysis is required to show that the building construction achieves an interior noise level of 45 dB(A) CNEL/Ldn or less.
8 Measurements are based on Ldn or CNEL.
3.0 Regulatory Framework
Impact Sciences, Inc. 17 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025
3.3 LOCAL PLANS AND POLICIES
City of Riverside General Plan 2025 Noise Element
The City of Riverside General Plan 2025 (General Plan) contains a Noise Element outlining the C ity’s policies and programs aiming to achieve and maintain noise levels compatible with various types of land uses. The noise objectives and policies from the General Plan that are relevant to the Project are listed below:
Objective N-1: Minimize noise levels from point sources throughout the community and, wherever possible, mitigate the effects of noise to provide a safe and healthful environment.
Policy N-1.2: Require the inclusion of noise-reducing design features in development consistent with standards in the Noise/Land Use Compatibility Criteria shown in Table 6, Noise / Land Use Compatibility Criteria, below, Title 24 California Code of Regulations and Title 7 of the Municipal Code.
3.0 Regulatory Framework
Impact Sciences, Inc. 18 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025 Table 7
Noise / Land Use Compatibility Matrix
Land Use Category
Community Noise Exposure (dB, Ldn or CNEL)
55 60 65 70 75 80 Single Family Residential
Infill Family Residential
Commercial- Transient Lodging - Motels Hotels
Schools, Libraries, Churches, Hospitals, Nursing
Homes
Auditoriums, Concert Halls, Amphitheaters
Sports Arena, Outdoor Spectator Sports
Playgrounds, Neighborhood Parks
Golf Courses, Riding Stables, Water Recreation,
Cemeteries
Office Buildings, Business Commercial and
Professional
Industrial, Manufacturing, Utilities, Agriculture
Normally Acceptable - Specific land use is satisfactory, based upon the assumption that any buildings involved are of normal conventional construction without any special noise insulation requirements.
Conditionally Acceptable - New construction or development should be undertaken only after a detailed analysis of the noise reduction requirements is made and needed noise insulation features included in the design. Conventional construction, but with closed windows and fresh air supply system or air conditioning will normally suffice.
Normally Unacceptable - New construction or development should generally be discouraged. If new construction or development does proceed, a detailed analysis of the noise reduction requirements must be made and needed noise insulation features included in the design.
Conditionally Unacceptable - New construction or development should generally not be undertaken, unless it can be demonstrated that noise requirements can be employed to reduce noise impacts to an acceptable level. If new construction or development does proceed, a detailed analysis of noise reduction requirements must be made and needed noise insulation features included in the design
Source: City of Riverside General Plan 2025, page N-23
3.0 Regulatory Framework
Impact Sciences, Inc. 19 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025 City Code of Riverside
Title 7 , Noise Control, of the City’s Municipal Code establishes standards concerning acceptable noise levels for both noise -sensitive land uses and for noise generating land uses. Sections from Title 7 that are relevant to the Project are listed below.
§ 7.25.010 Exterior sound level limits.
A. Unless a variance has been granted as provided in this title, it shall be unlawful for any person to cause or allow the creation of any noise which exceeds the following:
1. The exterior noise standard of the applicable land use category, up to five decibels, for a cumulative period of more than 30 minutes in any hour; or
2. The exterior noise standard of the applicable land use category, plus five decibels, for a cumulative period of more than 15 minutes in any hour; or
3. The exterior noise standard of the applicable land use category, plus ten decibels, for a cumulative period of more than five minutes in any hour; or
4. The exterior noise standard of the applicable land use category, plus 15 decibels, for the cumulative period of more than one minute in any hour; or
5. The exterior noise standard for the applicable land use category, plus 20 decibels or the maximum measured ambient noise level, for any period of time.
B. If the measured ambient noise level exceeds that permissible within any of the first four noise limit categories, the allowable noise exposure standard shall be increased in five decibel increments in each category as appropriate to encompass the ambient n oise level. In the event the ambient noise level exceeds the fifth noise limit category, the maximum allowable noise level under said category shall be increased to reflect the maximum ambient noise level.
C. If possible, the ambient noise level shall be measured at the same location along the property line with the alleged offending noise source inoperative. If for any reason the alleged offending noise source cannot be shut down, then the ambient noise must b e estimated by performing a measurement in the same general area of the source but at a sufficient distance that the offending noise is inaudible. If the measurement location is on the boundary between two different districts, the noise shall be the arithmetic mean of the two districts.
3.0 Regulatory Framework
Impact Sciences, Inc. 20 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025 D. Where the intruding noise source is an air- conditioning unit or refrigeration system which was installed prior to the effective date of this title, the exterior noise level when measured at the property line shall not exceed 60 dB(A) for units installed before 1 -1-80 and 55 dB(A) for units installed after 1 - 1-80.
Table 8, Exterior Noise Standards, describes the exterior noise standard by land use category.
Table 8
Exterior Noise Standards
Land Use Category Time Period Noise Level
Residential
Night (10:00 p.m. to 7:00 a.m.)
Day (7:00 a.m. to 10:00 p.m.)
45 dB(A)
55 dB(A)
Office/Commercial Any time 65 dB(A)
Industrial Any time 70 dB(A)
Community Support Any time 60 dB(A)
Public recreation facility Any time 65 dB(A)
Nonurban Any time 70 dB(A)
Source: City of Riverside, Code of Ordinances. Available online at:
https://library.municode.com/ca/riverside/codes/code_of_ordinances?nodeId=PTIICOOR_TIT7NOCO_CH7.23AMSOLE
§ 7.35.020 Exemptions.
The following activities applicable to the Project are exempt from the provisions of T itle 7 of City’s Municipal Code:
G. Construction. Noise sources associated with construction, repair, remodeling, or grading of any real property; provided a permit has been obtained from the City as required; and provided said activities do not take place between the hours of 7:00 p.m. and 7:00 a.m. on weekdays, between the hours of 5:00 p.m. and 8:00 a.m. on Saturdays, or at any time on Sunday or a federal holiday.
Impact Sciences, Inc. 21 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report - July 2025
4.0 NOISE ANALYSIS
4.1 THRESHOLDS OF SIGNIFICANCE
In accordance with Appendix G of the State CEQA Guidelines, impacts would be considered significant if the Project results in:
• Generation of a substantial temporary or permanent increase in ambient noise levels in the vicinity of the Project Site in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies;
• Generation of excessive ground-borne vibration or ground-borne noise levels; and • For a project located within the vicinity of a private airstrip or an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the Project expose people residing or working in the Project area to excessive noise levels.
The State CEQA Guidelines do not define the levels at which groundborne vibration or groundborne noises are considered “excessive.” Thus, in terms of construction -related vibration impacts on buildings, the adopted guidelines and recommendations by the FTA to limit groundborne vibration based on the age and/or condition of the structures that are located in close proximity to construct ion activity are used in this analysis to evaluate potential groundborne vibration impacts. Based on the FTA criteria, const ruction impacts relative to groundborne vibration would be considered significant if the following were to occur:
• Project construction activities would cause a PPV groundborne vibration level to exceed 0.5 inches per second at any building that is constructed with reinforced-concrete, steel, or timber; • Project construction activities would cause a PPV groundborne vibration level to exceed 0.3 inches per second at any engineered concrete and masonry buildings; • Project construction activities would cause a PPV groundborne vibration level to exceed 0.2 inches per second at any non-engineered timber and masonry buildings; or • Project construction activities would cause a PPV ground -borne vibration level to exceed 0.12 inches per second at any historical building or building that is extremely susceptible to vibration damage.
The State CEQA Guidelines do not define the levels at which noise would be considered substantial increases. Thus, for purposes of this analysis, the Project would normally have a significant impact on noise levels from project operations if the project causes the ambient noise level measured at the property line of
4.0 Noise Analysis
Impact Sciences, Inc. 22 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025 affected uses to increase by 3 dB( A) if the total ambient noise levels without the Project exceed the C ity’s General Plan exterior noise standards, or any 5 dB( A) or greater noise increase when total ambient noise levels without the Project are within the City’s exterior noise standards.
4.2 METHODOLOGY
Noise levels associated with P roject-related construction activities were calculated using the FHWA Roadway Construction Noise Model (RCNM) . Noise levels were also compared to the C ity’s noise ordinance, which includes provisions regarding construction noise levels. Specifically, Section 7.35.020 (Exemption) exempts noise sources associated with construction, repair, remodeling, or grading of any real property; provided a permit has been obtained from the City as required; and provided said activities do not take place between the hours of 7:00 p.m. and 7:00 a.m. on weekdays, between the hours of 5:00 p.m. and 8:00 a.m. on Saturdays, or at any time on Sunday or a federal holiday. 9 As the Project would comply with the daytime construction hours established in the City’s Municipal Code , this analysis also uses the FTA’s general construction noise criteria of 90 dB(A) Leq (1-hour)10 to provide additional context for the Project’s potential to generate daytime construction noise impacts.
An analysis of traffic noise was conducted to determine if the P roject would have a perceptible increase in traffic-related noise. Studies have shown that a 3 dB(A) increase in sound level pressure is barely detectable by the human ear. A 3 dB(A) increase in roadway noise levels requires an approximate doubling of roadway traffic volume, assuming that travel speeds and fleet mix remai n constant. 11 The Project’s potential to result in significant noise impacts from on -site operational noise sources was assessed by identifying sources of on-site noise sources and considering the impact that they could produce given the nature of the source (i.e., loudness and wh ether noise would be produced during daytime or more-sensitive nighttime hours), distances to nearby sensitive receptors, surrounding ambient noise levels, the presence of similar noise sources in the vicinity, and maximum allowable noise levels permitted by the City’s Municipal Code.
9 City of Riverside, Code of Ordinances, Title 7 – Noise Control, Chapter 7.23 – Ambient Sound Levels. Available online at:
https://library.municode.com/ca/riverside/codes/code_of_ordinances?nodeId=PTIICOOR_TIT7NOCO_CH7.23A MSOLE, accessed August 1, 2023.
10 Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual, Table 7-2 (General Assessment Construction Noise Criteria), September 2018. 11 California Department of Transportation (Caltrans), Technical Noise Supplement to the Traffic Noise Analysis Protocol, 2013. Available online at: https://dot.ca.gov/-/media/dot-media/programs/environmental- analysis/documents/env/tens-sep2013-a11y.pdf
4.0 Noise Analysis
Impact Sciences, Inc. 23 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025
4.3 IMPACT ANALYSIS
Impact NOI-1 Would the P roposed Project result in generation of a substantial temporary or permanent increase in ambient noise levels in the vicinity of the Project Site in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies? (Less than Significant).
Construction Impacts
Construction of the Project would require the use of heavy equipment for demolition, grading/site preparation, installation of utilities, building fabrication, and finishing. Construction activities would also involve the use of smaller power tools, generators, and other sources of noise. During each stage of construction, several types of equipment potentially could be operating concurrently and noise levels would vary based on the amount of equipment in operation and the location of the activity. The Fede ral Highway Administration’s (FHWA) Roadway Construction Noise Model (RCNM) has compiled data regarding the noise -generating characteristics of specific types of construction equipment and typical construction activities.
With the use of the RCNM, as detailed in Appendix A to this report, 12 the construction noise levels
forecasted for the sensitive receptors are presented in Table 9, Estimated Exterior Construction Noise at Sensitive Receptors. Noise levels would diminish notably with distance from the construction site at a rate of 6 dB(A) per doubling of distance (noise from stationary or point sources is reduced by about 6 dB(A) for every doubling of distance at acoustically hard locations). For example, a noise level of 86 dB (A) Leq measured at 50 feet from the noise source to the receptor would decline to 80 dB( A) Leq at 100 feet from the source to the receptor and fall by another 6 dB(A) Leq to 74 dB(A) Leq at 200 feet from the source to the receptor. These noise attenuation rates assume a flat and unobstructed distance between the noise generator and the receptor. Intervening structures and vegetation would further attenuate (reduce) the noise. Furtherm ore, it should be noted that i ncreases in noise levels at sensitive receptors during construction would be intermittent and temporary and would not generate continuously high noise levels.
In addition, the construction noise experienced at sensitive receptors during the initial periods of construction (i.e., demolition, site preparation/grading/foundations) typically would be reduced in the later construction periods (i.e., interior building construction).
12 Project construction noise levels were calculated based on the Project’s anticipated mix of construction equipment with the FHWA RCNM Version 1.1.
4.0 Noise Analysis
Impact Sciences, Inc. 24 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025
Table 9
Estimated Exterior Construction Noise at Sensitive Receptors
Sensitive Land Usesa
Distance to Project
Site (feet)
Estimated Construction
Noise Levels
[dB(A) Leq]
Exceed FTA 90
dB(A) 1-Hour Leq
Criteria?
1. Adjacent residences to the north Adjacentb 75.4 No
2. Adjacent residences to the south Adjacentb 74.2 No
3. Residences to the west on Hedrick Avenue 40 69.5 No
4. Residences to the East on Jones Avenue 54 69.4 No
a See Figure 3 for locations of sensitive receptors.
b While the project would include construction activities up to the adjacent property lines, consistent with FTA methodology, these calculations are based on distances from the center of the site to the receptors.
See Appendix A to this report.
Temporary construction, maintenance, repair, and demolition activities are exempt from the Ci ty Code regulations regarding noise so long as the temporary construction does not take place between the hours of 7:00 p.m. and 7:00 a.m. on weekdays, between the hours of 5:00 p.m. and 8:00 a.m. on Saturdays, or at any time on Sunday or a federal holiday .
13 As the Project would comply with the daytime construction hours established in the City’s Municipal Code, this analysis also uses the FTA’s general construction noise criteria of 90 dB(A) Leq (1-hour) to provide additional context for the Project’s potential to generate daytime construction noise impacts. While construction activity would increase noise levels in the vicinity of the Project Site (see Table 9), t he Project’s construction activities would not exceed the FTA’s general construction noise criteria of 90 dB(A) Leq (1-hour) at any sensitive receptors. Furthermore, Project construction would not occur during restricted periods, and thus, the Project would be consistent with the criteria set forth in the Ci ty Code. As such, construction noise impacts would be less than significant and no mitigation is required.
In addition to adherence to the City of Riverside Municipal Code which limits the construction hours, the following best management practices (BMPs) are recommended that would further reduce noise levels associated with the construction of the Project.
13 City of Riverside, Code of Ordinances, Title 7 – Noise Control, Chapter 7.23 – Ambient Sound Levels. Available online at:
https://library.municode.com/ca/riverside/codes/code_of_ordinances?nodeId=PTIICOOR_TIT7NOCO_CH7.23A MSOLE, accessed August 1, 2023.
4.0 Noise Analysis
Impact Sciences, Inc. 25 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025
1. During all Project grading on- site, construction contractors shall equip all construction equipment, fixed or mobile, with properly operating and maintained mufflers, consistent with manufacturer standards.
2. The contractor shall place all stationary construction equipment so that emitted noise is directed away from noise sensitive receptors nearest the project site.
3. As applicable, all equipment shall be shut off and not left to idle when not in use.
4. The contractor shall locate equipment staging in areas that will create the greatest distance between construction-related noise/vibration sources and sensitive receptors nearest the project site during all project construction.
5. Jackhammers, pneumatic equipment and all other portable stationary noise sources shall be shielded and noise shall be directed away from sensitive receptors.
6. The project proponent shall mandate that the construction contractor prohibit the use of music or sound amplification on the project site during construction.
7. The construction contractor shall limit haul truck deliveries to the same hours specified for construction equipment.
Operational Impacts
Permanent Operational Traffic Noise
A traffic analysis for the Project was prepared by CR Associates.14 Based on the traffic analysis contained therein, the Project is anticipated to generate approximately 789 average daily traffic (ADT). 15 The closest roadway to the Project Site with a recorded average daily traffic volume is Tyler Street , located approximately 2,800 feet northeast of the Project Site. According to City data, this roadway segment carries approximately 17,203 average daily trips at Wells Avenue.16 Based on this data, it is clear the Project’s maximum of 789 daily trips would not have the potential double traffic volumes on existing roadways in the vicinity of the Project Site. Since it would take a doubling (i.e., a 100% increase) of roadway traffic volume to increase noise levels by 3 dB(A), the addition of traffic volume from operation of the Project would not increase traffic to levels capable of producing a 3 dB(A) ambient noise increase. Additionally,
14 Chen Ryan Associates, Mikasa Multi Family Project Traffic Analysis, April 2025. 15 Chen Ryan Associates, Mikasa Multi Family Project Traffic Analysis, April 2025. 16 City of Riverside, “24 Hour Volume Counts,” available at: https://riversideca.gov/pdf2/traffic-volume-count.pdf
4.0 Noise Analysis
Impact Sciences, Inc. 26 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025 the Project is consistent with the surrounding land uses , which currently generate mobile noise sources typical of a residential neighborhood . As such, any noise increase would be imperceptible, and impacts would be less than significant.
Stationary Noise Sources
As part of the Project, new mechanical equipment, HVAC units, and exhaust fans could be installed on or near the proposed new structures. Although the operation of this equipment would generate noise, the design of these on-site HVAC units and exhaust fans would be required to comply with the regulations of the City’s Municipal Code . Specifically, Section 7.25.010 (Exterior Sound Level Limits) states that for stationary noise sources such as an air-conditioning unit or refrigeration system, the exterior noi se level when measured at the property line shall not exceed 60 dB(A) for units installed before 1-1-80 and 55 dB(A) for units installed after 1 -1-80. As such, compliance with Section (Exterior Sound Level Limits) and other applicable regulations would ensure noise from stationary sources would be less than significant.
Impact NOI-2 Would the P roposed Project result in the generation of excessive groundborne vibration or groundborne noise levels? (Less than Significant).
The FTA provides ground -born vibration impact criteria with respect to building damage during construction activities. PPV, expressed in inches per second, is used to measure building vibration damage.
Construction vibration damage criteria are assessed based on structural category (e.g., reinforced-concrete, steel, or timber). FTA guidelines consider 0.2 inch/sec PPV to be the significant impact level for non - engineered timber and masonry buildings. Structures or buildings constructed of reinforced concrete, steel, or timber have a vibration damage criterion of 0.5 inch/sec PPV pursuant to FTA guidelines. Although the nearby structures appear to be constructed of reinforced concrete, steel, or timber, this analysis conservatively applies the 0.2 inch/sec PPV threshold typically applied to non -engineered timber and masonry buildings.
The vibration levels at nearby structures are shown below in Table 10, Vibration Levels at Off -Site Structures from Project Construction.
4.0 Noise Analysis
Impact Sciences, Inc. 27 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report – July 2025
Table 10
Vibration Levels at Off-Site Structures from Project Construction
Sensitive Uses Off-Sitea Distance to Project Site (ft.) Vibration Threshold (PPV)
Estimated PPV
(in/sec)
1. Adjacent residences to the north Adjacentb 0.2 in/sec 0.191
2. Adjacent residences to the north Adjacentb 0.2 in/sec 0.191
3. Residences to the west on Hedrick Avenue 40 0.2 in/sec 0.044
4. Residences to the east on Jones Avenue 54 0.2 in/sec 0.028
a See Figure 3 for locations of off-site structures.
b These calculations are based on distance from the site boundary to the structures. See Appendix A to this report.
The vibration velocities predicted to occur at the nearest off -site structures would be 0.191 in/sec PPV. As shown in Table 10, Project construction vibration levels would not have the potential to exceed the standard 0.2 in/sec threshold established by the FTA. This impact would be less than significant.
Impact NOI-3 For a project located within the vicinity of a private airstrip or an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport, would the project expose people residing or working in the project area to excessive noise levels? (Less than Significant).
The Project Site is not located within the vicinity of a private airstrip or an airport land use plan and is not located within 2 miles of a public airport or public-use airport. The closest airport, the Riverside Municipal Airport, is located approximately 3.5 miles northeast of the Project Site. Therefore, no impacts with respect to airstrip or airport related noise would occur and no further analysis is required.
Impact Sciences, Inc. 28 Mikasa Luxury Villas Residential Development Project 1558.001 Noise and Vibration Technical Report - May 2025
5.0 REFERENCES
California Department of Transportation (Caltrans). Technical Noise Supplement to the Traffic Noise Analysis Protocol. 2013. Available at: https://dot.ca.gov/-/media/dot-media/programs/environmental- analysis/documents/env/tens-sep2013-a11y.pdf
Caltrans, Transportation and Construction Vibration Guidance Manual, 2020.
CR Associates, Mikasa Multi Family Project Traffic Analysis, April 2025.
City of Riverside. Code of Ordinances. Chapter 7.23 - Ambient Sound Levels. Available online at:
https://library.municode.com/ca/riverside/codes/code_of_ordinances?nodeId=PTIICOOR_TIT7N OCO_CH7.23AMSOLE, accessed August 15, 2023.
City of Riverside. City of Riverside General Plan 2025, Noise Element, Available online at:
https://riversideca.gov/cedd/sites/riversideca.gov.cedd/files/pdf/planning/general- plan/10_Noise_Element_with%20maps.pdf, accessed August 15, 2023.
City of Riverside. “24 Hour Volume Counts.” Available online at: https://riversideca.gov/pdf2/traffic- volume-count.pdf, accessed August 15, 2023.
Federal Highway Administration. Highway Noise Fundamentals. (1980) 97.
Federal Highway Administration. Highway Noise Mitigation. (1980) 18.
Federal Highway Administration. Highway Traffic Noise: Analysis and Abatement Guidance. December 2011.
Federal Transit Administration. Transit Noise and Vibration Impact Assessment Manual. 2018. Available online at: https://www.transit.dot.gov/sites/fta.dot.gov/files/docs/research- innovation/118131/transit-noise-and-vibration-impact-assessment-manual-fta-report-no- 0123_0.pdf, accessed August 15, 2023.
Impact Sciences. CalEEMod Output for the Mikasa Luxury Villas Residential Development Project . 2023.
United States Department of Labor. Occupational Safety and Health Act of 1970. Available online at:
https://www.osha.gov/laws-regs/oshact/completeoshact, accessed May 2021.
United States Occupational Safety & Health Administration. Noise and Hearing Conservation Technical Manual. 1999.
APPENDIX A
Noise and Vibration Technical Data